Leather working machine and safety device therefor



Nov. 25, 1941. w, RUSSELL 2,2645053 LEATHER WORKING MACHINE AND SAFETY DEVICE THEREFOR Filed May 23, 1939 3 Sheets-Sheet l NQV. 25, 1941.

w. RUSSELL 2,264,053 LEATHER WORKING MACHINE AND SAFETY DEVICE THEREFOR v led 1939 -3 Sheets-Sheet 2 /6 f5 I26 42 56 Nov. 25,1941. w, @SSELL- 2,264,053

' LEATHER WORKING MACHINE AND SAFETY DEVICE THEREFOR Filed May 23, 1939 3 SheetS -Sheet 3 E w M Patented Nov. 25, 1941 LEATHER WORKING MACHINE AND SAFETY DEVICE THEREFOR Winn Russell, Woburn, Mass.

Application May 23, 1939, Serial No. 275,178

16 Claims.

This invention relates to leather working machines and particularly to leather bufilng and analogous machines and to protective devices therefor.

The bufiing machine with which the present invention is particularly concerned comprises a large fast moving cutting roll or drum having an abrasive surface. The successive leather sheets or skins are fed to the action of the drum by a pair of cooperating superposed rolls. The upper roll is an idler roll and is located in front of the drum and journalled in vertically swinging arms which are free for vertical movements although the lowermost position of the roll is limited by stops. The idler roll by its weight or the weight of its supporting arms presses the work on the lower roll which is the driven feed roll and usually is rubber surfaced while the idler roll has a polished surface. Said feed roll is journalled in a carriage which can be moved toward and away from the cutting drum by pedal controlled mechanism. operated by the operative. The mechanism is so arranged that the feed roll is maintained normally under the idler roll and close to the cutting drum but can be moved away from both rolls by the depression of the pedal by the operative. In use the pedal is intended to be depressed and the feed roll withdrawn while the operative arranges a leather sheet or skin fiat on a table of the carriage and with the leading edge of the sheet on the feed roll. The pedal then is released to permit the advance of the roll and the sheet on the table toward the drum and into the bite of the feed and idler rolls whereupon the sheet is advanced by the action of the rolls to the buffing action of the drum. As the leather advances it must be kept flat and free from wrinkles so that the operative has to smooth out the wrinkles and his hands are thus close to the rolls. Machines of this type have proven to be quite dangerous in use and there are numerous instances of accidents where the fingers of an operative are caught in the pinch of the rolls and his hand and arm are drawn against the drum. While the hand can be released by stepping on the treadle the operative at this time usually does not think of doing this and also at this time is in an awkward position for depressing the treadle' and "as a consequence serious injury can be incurred.

An object of the present invention is the provision of a buffing or analogous machine prO- vided with safety mechanism automatically operative to prevent the hand of the workman from being drawn into contact with the cutting drum.

Another object of the invention is the provision of a leather working machinewherein mechanism is provided for stopping the rotation of the feed roll when an object of unusual thickness enters between the rolls.

A. yet further object of the invention is generally toimprove the construction and operation of leather working machines and particularly buffing and allied machines. g a

Fig; 1 is a front elevation of a bufilng machine embodying the present invention; the'usual dust hood over the cutting drum being removed.

Fig.2 is an end elevation of the machine of Fig. 1.

Fig. 3 is a perspective detail of the mechanism for locking the feed roll against rotation.

Fig. 4 is a detailed sectio'nal'elevation of the tripping mechanism for the locking means' Fig. 5 is a sectional detail of a circuit'controller taken along line 5--5 of Fig. 2.

Fig. 6 is a front elevation in detail of a modified form of purely mechanical means for locking the feed roll against rotation.

The leather buffing machine herein illustrated as embodying the present invention includes a supporting structure having a pair of end frames I0 and I2 each provided with a. horizontal top beam or bar M. A relatively large abrasivesurfacedcutting roll or drum I6 is located between the end frames and has its shaft I 3 rotatably supported in suitable bearings 20 carried by said end frames. The right hand end of the shaft is connected to a suitable driving motor or other driving means not herein shown that rotate the drum at a relatively high surface speed. The forward part of the horizontal bars M are provided with longitudinally extended grooves 2| which guide carriages 22 and 24 on said bars for horizontal movement toward and away from the drum. Said carriages are connected rigidly together by and provide support for a horizontal table 26 which upstands above the carriages in front of the drum. Said carriages have upstanding ears 28 and the table has depending ears 30 that are clamped together by bolts 32 passing through vertically elongated slots 34 in the carriage ears 28 whereby the vertical elevation of the table can be adjusted.

The carriage provides support for a feed roll 36 which usually is provided with a rubber work engaging face. The shaft 38 of the feed roll is journalled in suitable bearings 40 carried by and rising above the rear parts of the carriages between the table and the cutting drum. The vertical adjustment of the table is such that the plane of the top of the table is approximately tangential with the top of the feed roll.

The shaft 38 of the feed roll at the end pro.- jecting beyond th end frame I2 is provided with a driving pulley 42 receiving a pair of V-belts 44 which are driven by a pulley 46 rotatably carried by a shaft 41 located at the lower part ofthe end frame I2. Said pulley 46 is in driven relation with a cone pulley 48 driven through a belt 50 from a cone pulley 52 fixed to and driven by the drum shaft I8.

An idler roll 54 cooperates with the feed roll and is located thereabove. The end parts of the shaft 56 of said idler roll are journalled in the forward ends of a pair of forwardly projecting arms or links 58 and 60 extending horizontally rearwardly over the bearings for the drum shaft and having pivotal connections at 62 with the upper parts of upstanding projections 64 rising from the top beams or bars I4 of the end frames. Adjustable stop members 68 carried by said arms 58 and 80 intermediat their ends engage the upper faces of posts 68 rising from the beams I4 forwardly of the drum shaft bearings 20. The weight of the roll and the arms is such that the stop members are maintained by gravity in engagement with said posts but the roll and arms can move vertically to accommodate sheets of various thicknesses.

In the operative position of the rolls the lower or feed roll 36 is in a rearward position where its periphery is sufficiently close to the surface of the cutting drum to hold a leather sheet therebetween in cutting contact with the drum. The idler roll 54 engages the sheet on the feed roll somewhat rearwardly of the vertical plane through the axis of the feed roll, as illustrated in Fig. 2.. When the sheet A on the table 28 is pinched between said rolls the sheet is advanced to the action of the cutting drum. The rearmost position of the feed roll is governed by adjusting screws I carried by the carriages and disposed to abut against the forward ends of the end frames.

The carriage is retracted or moved towards the operative and away from the cutting drum to position a fresh sheet upon the table and the feed drum by means including treadle mechanism operated by the foot of the operative. The treadle mechanism includes a cross bar I2 located in frontof the machine at the lower part thereof and fixed to the outer ends of levers I4 fixed to a pedal shaft I6 journalled in bearings 10 of the machine. frame. Said levers in the rear of, said shaft 16 are pivotally connected to upwardly extending lengthwise adjustable rods I9, the up tracted position when the pressure of the opera-,

tive on the pedal I2 is released.

The: rear ends of the.;

Iii

The leather sheets or skins A are usually relatively broad with irregular contours and must be kept fiat as the sheets are advanced between the rolls so as to prevent the formation of wrinkles; and wrinkles sometimes form just as the leather passes into the bite of the rolls. Thus the workmans hand is frequently close to the rolls.

In accordance with the present invention, means are provided for preventing the hand from being fed by the rolls into contact with the cutting drum. Said mechanism, as herein specifically illustrated, includes means for stopping the rotation of the feed roll 36 in th event the hand is drawn into the space between the feed roll 36 and the idler roll 54. Such mechanism includes an externally toothed member or gear 84, similar to a sprocket, fixed on the shaft 38 of the feed roll adjacent the side frame I0. A bracket 86 is fixed to the top face of the top bar I4 of the end bar #0 and has a depending ear 88 to which the forward end of a pawl or stop lever 90 is pivoted by the screw 92. Said lever projects rearwardly under the table 26 and has a rear end part 94 positioned when elevated to enter the space between any consecutive two teeth 96 of the sprocket. The sprocket rotates in a counter-clockwise direction, Fig. 2, and hence the sprocket rotates against the free end of the lever and thus the sprocket is caused to be held stationary against the driving action of the belts 44, the belts thus slipping in their engagement either with the pulley 42 or the pulley 46. A retra-ctile spring 98 connected between an intermediate part of the stop lever 90 and the table 26 serves to urge the lever upwardly into looking position when permitted to do so and to hold the lever in such locking position until it is manually restored to an unoperated position shown in Figs. 2 and 3.

The operation of the lever is controlled by a vertical latch rod I00, the lower end of which bears releasably upon the top part of the stop lever and the upper end of which is pivoted at I02 to a boss I04 rising from the inner face of the bottom wall I06 of an enclosing casing I08, fixed to the under face of the table 26. A spring IIO bears on said latch rod to urge it releasably into normal vertical latching position against an adjustable stop member I I2, in which position the lower end of the latch rod is in engagement with the stop or locking lever and holds it from upward movement.

Release of the lever for locking movement is accomplished by moving the latch rod in a counterclockwise direction or toward the right, Figs. 3 and 4. Such movement is effected by an electromagnet II4 located within the enclosing casing I08 and having .an energizing winding I I6 and an armature I I8 connected loosely by a strap I20 with the latch rod. The winding H8 is adapted normally to be un-energized and the armature is thus normally in an unattracted position. When, however, the winding is energized the armature is moved toward the right and thereby displaces the latch rod from holding engagement with the stop lever so that the stop lever moves upwardly under urge of the spring 98 into holding engagement with the gear on the feed roll shaft.

Control of the electromagnet is accomplished by means of a pair of normally circuit open switches or circuit controllers IZI, I23 each associated with a separate one of the arms 58, supporting the idler roll shaft. Said switches are or can be of mor or less common construction and a suitable one is illustrated in Fig. 5.

'IIG.

The switch includes a casing IZI having therein a movable contact member I22 and a cooperating stationary contact member I24. The switch operating mechanism includes a vertically movable rod I26 which depends below the bottom of the casing and terminates close to the upper face of the associated roll supporting arm 58 or '60. The rod carries a disc I28 urged constantly in an upward direction by a spring I30 and restricted in its upward movement by ashoulder I32 of said rod I26. Thus a small amount of vertical displacement of the operating pin I26 is suflicient to effect circuit closing engagement of the contact members and yet the operating pin I26 can be displaced further in an upward direction without damage to the switch and while maintaining the contacts closed.

The switch casing is provided with a laterally extending arm I34 which is fixed to the upper end of a vertical rod I36, the lower end of which is vertically adjustably secured in a bracket I38 fixed to the side face of a post 66. With this arrangement the clearance between the switch pin I26 and the associated roll carrying arm can be conveniently adjusted.

Both switches I 2 I, I23 are in parallel with each other and in series with the energizing winding Thus when either switch is operated the winding is energized and the feed roll is stopped from rotating. The use of a switch for each roll arm is desirable because the idler roll is purposely so mounted that it can adjust itself for uneven thicknesses of leather along its length and hence the axis of the roll can tilt with respect to the axis of the feed roll. Thus if one switch alone is utilized it is possible for the hand of an operative to enter the bite of the rolls remot from the arm associated with the switch with the possibility that the switch would not be operated and the feed roll stopped from rotation until the separation of the rolls was so great as to effect the raising of the supporting arm associated with the switch.

With this arrangement the leather sheets can be passed between the rolls in the usual manner without causing the switches to be operated. When, however, some thicker object, as the finger of an operative, enters between the rolls the idler roll is raised an undue amount and effects the closing of one or another of the switches and 50 the consequent stoppage of the rotation of the feed roll. This action takes place before the hand can be fed by the rolls sufficiently to come into contact with the cutting drum. Thus there is, no danger of the hand becoming injured by the drum. The carriage with the feed roll can then be retracted by the depression of the pedal 12 and the hand released from the rolls. The pressure of the idler roll on the hand is not of itself sufficient to injure the hand. After the safety device has been operated it is reset by moving the locking lever 90 downward away from engagement with the gear 84 and held releasably in such position by the restoration of the latch rod I00 into holding position thereover and in engagement therewith.

In the modification illustrated in Fig. 6 a purely mechanical mechanism is employed. The stop or looking lever 90a is employed as before together with the latch rod I00a which, in this instance,' is pivotally secured directly to the table 26a. The arm 58a carries one end of the idler roll and is provided with a laterally projecting ear I42 in which a headed vertical rod I44 is loosely located, the lower end of the rod passing loosely through a lateral extension I46 of the latch rod. The lower end of the rod I44 is screw-threaded and provided with a nut I48 by which the amount of vertical movement of the idler roll prior to effecting the locking of the feed roll can be adjusted. With this arrangement when the roll supporting arm 58a is sufliciently elevated the latch rod I00a is caused to swing in a clockwise direction away from holding engagement with the locking lever 90a thereby causing the upward movement of said lever under the urge of the spring I40 into locking engagement with the gear 8411 on the feed roll shaft as heretofore.

In this modification the release of the latch rod is controlled by the roll supporting arm 58a. Said arm, however, is caused to move vertically in response to vertical movement of the other roll supporting arm 60a. To this end the arm 58a is connected to one end of a flexible cable I 50 which extends vertically upward above the arm and passes over a pulley I 52 journalled in a bracket I54 fixed to an end frame of the machine and thence passes horizontally to the other end of the machine where it is connected to one end of a turn buckle I56. The other end of said turn buckle is connected to a vertical arm I53 of a bell crank lever the horizontal arm I60'o1 which bears uponthe top part of the roll supporting arm 60a. The bell crank lever is pivoted at I62 to a bracket I64 fixed to the end frame I2 of the machine. A weight I66 acting through a flexible cable I68 passing over an elevated pulley I I0 and having its free end connected to the supporting arm a serves to maintain said arm against the short arm I 60 of the bell crank lever and thus places the cable I50 under tension. With this arrangement if the obstruction between the feed and idler rolls is located near the arm 60a said arm is raised and through the cable I50 causes the arm 58a to be raised thereby operating the safety mechanism and effecting the stoppage of the feed roll as has been heretofore explained. The cable I50 also serves as a convenient tripping means for the safety mechanism in that pressure on the cable in any direction will effect the release of the latch rod and the stoppage of the feed roll.

I claim:

1. In a leather working machine comprising a cutting drum, a driven feed roll, a reciprocable carriage constituting a support for said feed roll and by which said feed roll is positioned adjacent to and also remote from said cutting drum, an idler roll disposed above said feed roll, and supporting means for said idler roll operative to permit displacement of said idler roll toward and away from said feed roll, the combination therewith of means responsive to a predetermined displacement of said idler roll operative substantially instantly to lock said feed roll against rotation in a feeding direction.

2. In a leather working machine comprising a cutting drum, a pair of cooperating feed 'rolls for advancing work toward said drum, and supporting means for said drum permitting the displacement of one of said rolls relatively to the other to accommodate work of variable thickness therebetween. the combination therewith of electromagnetic feed control means responsive to the presence of an object of unusual thickness between said rolls for preventing the feeding of said object.

3. In a leather working machine comprising a cutting drum, a driven feed roll, an idler roll cooperating with said feed roll, and independent- 1y vertically displaceable arms in which said idler roll is supported permitting displacement of said idler roll with respect to said feed roll, the combination therewith of feed controlling means controlling the rotation of said feed roll, and means responsive to a predetermined dis.- placement of any one or both of said arms ifor effecting operation of said feed controlling means.

4. In a leather working machine comprising a 'cuttingdrum, a driven feed roll, an idler roll cooperating with said feed roll, and independently vertically displaceable arms in which said idler roll is supported permitting displacement of said idler roll with respect to said feed roll,

the combination therewith of .electroresponsive feed controlling means controlling the rotation of said feed roll and circuit controlling switches means, and circuit controlling means for said electro-responsive means.

6. In a leather working machine comprising a cutting drum, a feed roll for advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said roll, a stop member movable into engagement with said toothed member for holding it and said roll against rotation, and means controlling the operation of said stop member.

'7. In a leather working machine comprising a cutting drum, a feed roll for advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said feed roll, a stop member movable into engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such movement, and means for moving said latch member from its restraining relation with said stop member.

8. In a leather working machine comprising a cutting drum, a feed roll for advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said feed roll, a stop member movable into engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such move ment, electromagnetic means for moving said latch member from its restraining position with respect to said stop member, and a circuit controller controlling the energization of said electro-responsive means.

9. In a leather working machine comprising a cuttingdrum, a feed roll for advancing workto the action of said drum, and driving means ffdr said feed roll, the combination therewith of a toothed member fixed to said feed roll, a, stop member movable into. engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such movement, an idler roll cooperating with said feed roll, supporting means for said idler roll permitting displacement thereof with respect to said feed roll, and means responsive to a predetermined displacement of said idler roll for freeing said latch member from its restraint on said stop member.

10. In a leather working machine comprising a cutting drum, a feed roll for advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said feed roll. a stop member movable into engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such movement, an idler roll cooperating with said feed roll, pivotally mounted arms in which said idler roll is journalled permitting displacement of said idler roll with respect to said feed roll,- and means responsive to the displacement of any one of both supporting arms for effecting movement of said latch member into a position free from restraint on said stop member.

11. In a leather working machine comprising a cutting drum, a feed roll for advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said feed roll, a stop member movable into engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such movement, an idler roll cooperating with said feed roll, supporting means for said idler roll permitting separate displacement of the ends of said idler roll with respect to said feed roll, and means responsive to a predetermined displacement of any one of the ends of said idler roll for effecting removal of said latch member into a position free from restraint on said stop member.

12. In a leather working machine comprising a cutting drum, a feed rollfor advancing work to the action of said drum, and driving means for said feed roll, the combination therewith of a toothed member fixed to said feed roll, a stop member movable into engagement with said toothed member for holding it and said roll against rotation, means constantly urging said stop member for movement into engagement with said toothed member, a latch member normally restraining said stop member against such movement, an idler roll cooperating with said feed roll, supporting means for said idler roll permitting separate displacement of the ends of said idler r011 from said feed roll, electromagnetic means for moving said latch member into a position free from restraint on said stop member, and circuit controlling members separately associated with the end parts of said idler roll and separately responsive to a predetermined displacement of an end of said idler roll for energizing said electro-magnetic means.

13. In a leather working machine comprising a cutting drum, co-acting feed rolls for advancing work toward said drum, driving means for one of said feed rolls, electro-responsive feed control means for preventing the rotation of said driven roll, pivotally mounted supporting arms in which said other roll is journalled admitting displacement of said other roll toward and away from said driven feed roll, a circuit controller for said electro-responsive feed control means having an operating member disposed in position to be engaged and operated by a predetermined displacement of one of said arms, supporting means for said circuit controller, and means associated with said circuit controller for setting said circuit controller for operation at a predetermined displacement of said arm.

14. In a leather working machine comprising a cutting drum, a pair of cooperating feed rolls for advancing work to said drum, driving means for one of said rolls, pivotally mounted supporting arms for said other roll permitting displacement of said other roll toward and away from said driven roll, the combination therewith of electromagnetic means for stopping the rotation of said driven roll, and a circuit controller for said electromagnetic control means having an operating member responsive to a predetermined displacement of a roll supporting arm for efiecting operation of said feed control means, said controller having means permitting further displacement of said arm in the same direction Without changing the operated condition of said circuit controller.

15. In a leather working machine, a cutting drum, a pair of upper and lower feed rolls in front of said drum, driving means for the lower roll, supporting means for each end of the upper roll capable of independent displacement with said roll toward and away from said lower roll, means interconnecting both of said supporting means to effect displacement of one supporting means in response to displacement of the other supporting means, arranged to be moved directly by one supporting means and responsive to a predetermined displacement of each supporting member, and means controlled by said member for stopping the feeding operation of said rolls.

16. In a leather working machine, a cutting drum, a pair of cooperating feed rolls located in front of said drum, driving means for one of said feed rolls, the other roll being a rising and falling roll, feed control means responsive to abnormal displacement of said rising and falling roll operative to stop the feed action of said rolls, and a manually engageable control member extended above and lengthwise of said feed rolls arranged to respond to pressure thereon to displace said rising and falling rolls abnormally and effect operation of said feed control means.

WlNN RUSSELL. 

